User blog comment:TheDarkMaster102/Altaria Moveset/@comment-31433193-20161230040436

Altaria is a mediocre Pokémon with average stats in the metagame. However, with the Mega Stone equipped, it can be a devstating monster whose appearance is a fluffy cotton candy. Mega Altaria basically invested in an all-rounded stat overall, and can be either a Special Attacker, Physical Attacker, or a Defensive Bulk. With such diversity, Mega Altaria serves a great role as a Mega Evolution on the field with the ultimate Dragon-Fairy typing tocounter other Dragon-types.

Altaria @ Altarianite

Adamant/Jolly: 252 Atk / 4 Def / 252 Spe

Dragon Dance (Relearn) / Return (TM - BP Shop) / Roost (TM - BP Shop) / Earthquake (TM - BP Shop)

Other option: Replace Roost with Flamethrower (TM - BP Shop)

Max Attack and Speed for Mega Altaria is pretty much self-explanatory if it acts as an offensive attacker. Adamant for more power; Jolly to outspeed certain dangerous Pokémon. Dragon Dance is basically an essential setup for Mega Altaria to hit everythin like a truck, alongside gaining Speed. Thanks to Pixilate, Mega Altaria's ability, Normal-type attacks will turn into Fairy-type attacks and gets powered up. Return, with maximum happiness, does base 102 damage and getting a boost, will be a crazy amount of damage dealt to the opponent. Hence, it will be your main STAB move (Mega Altaria is now Dragon-Fairy) that you should spam over and over again when attacking. Roost assists Mega Altaria to regain health whenever suffering damage in order to regain momentum and extend time on the field. Earthquake is to hit those annoying Steel-types and Poison-types which resists your Fairy-Return. If you feel uncomfortable with Mega Scizor or Ferrothorn, go ahead and replace Roost with Flamethrower. You do not really need a Dragon-type attack as Fairy-Return will work against Dragons, which Dragon-types are only supper-effective to its own.

Like I said, there are a lot of other sets to play around with. Special set with Flamethrower + Moonblast + Dragon Pulse, a bulky set with Cotton Guard and Roost... enjoy your time to develop what you need for your TEAM; that is the most important thing to consider.